Code Readability: Quick, Millions or Billions? →
Ruby allows underscores to be inserted into numbers between any two digits. The underscores are purely cosmetic and do not affect the value of the number. This feature allows a developer to use underscores as an accountant might use commas.
3193490646 # standard representation of a number in ruby
3_193_490_646 # same value, much more readable
One less excuse for order of magnitude errors when using ruby.
